Search results for "Turbulence intensity"
showing 2 items of 2 documents
Analysing longitudinal turbulence intensity in vegetated channels
2007
Vegetation altering hydrodynamic conditions of an open channel flow controls the exchanges of sediment, nutrients and contaminants. In this paper the turbulence structure of open-channel flow over a flexible grass vegetation is investigated. Velocity measurements were carried out, in a rectangular flume, using a 2D-ADV (Acoustic Doppler Velocimeter) for different values of stem concentration, water discharge, and bed slope. The experimental results showed that: 1) the maximum value of the longitudinal turbulence intensity occurs at a water depth close to the bent vegetation height; 2) the turbulence intensity damps for increasing values of the stem concentration; 3) above the vegetation hei…
Large eddy simulations on the effect of the irregular roughness shape on turbulent channel flows
2019
Abstract Large Eddy Simulations (LES) are carried out to investigate on the mean flow in turbulent channel flows over irregular rough surfaces. Here the attention is focused to selectively investigate on the effect induced by crests or cavities of the roughness. The irregular shape is generated through the super-imposition of sinusoidal functions having random amplitude and four different wave-lengths. The irregular roughness profile is reproduced along the spanwise direction in order to obtain a 2D rough shape. The analysis of the mean velocity profiles shows that roughness crests induce higher effect in the outer-region whereas roughness cavities cause the highest effects in the inner-reg…